240SX Throttle Body

  Craig Borden  


SX-Z_TB_comp2-250.GIF (45065 bytes)I finally gave up on my search for one of the TWM throttle body (TB) units at a bargain price. After lurking in the online forums for a while I decided that I would go with a late model Nissan TB from a 300ZX or 240SX. A trip to the largest local scrap yard found several of the units I wanted but they wanted $150! That was insane! So, I went to a guy's house that I knew used to keep some Nissans around and lucked up. I got a TB unit from a 1989 240SX, 240SX fuel rail (which I like!), pulleys, throttle cable and pedal and other knick-knacks for $70. I felt it was a pretty good deal and I was running short on time. As a side note: I was surprised to see that the 240SX motor is basically a chopped off L6. I guess Nissan figured it wasn't a platform to mess with.
I don't plan on using the SX TB until I go to an aftermarket engine management system but I may just get the itch to bolt it on! In reality this will not be a good thing to do. The ECU of the Z car is not suitable for this upgrade and it would cause some dangerous conditions for my engine. It is mostly just wishful thinking!
SX-Z_TB_comp250.gif (54582 bytes)The SX throttle body has a 60mm bore and the Z is 50mm. Measurements were made across the OUTLET of the throttle body bores. The inlets are larger and taper down to the butterfly so a true measurement cannot be taken at the inlet.
Notice that the Z TB unit will fit into the SX TB with room to spare.
The SX unit must be mounted upside down so that the throttle linkage will be on the same side as the Z unit. The SX linkage rod is quite a bit longer than the Z rod and will interfere with the #1 intake runner on the Z manifold.
A spacer could be fabricated to space the SX TB away from the intake for clearance but this would probably be an expensive solution if a quality spacer is fabricated.
The SX unit has provisions for 2 throttle cables on the throttle shaft. One is for the accelerator pedal and the other for cruise control. I had no plans for cruise control (hmmmmm...) so I opted to remove the outermost cable "channel" and springs. Then I was able to cut off the excess of the throttle shaft, re-thread the end of the shaft and create the needed clearance.
I do plan on converting the shaft linkage on my Z to the cable linkage as used on the SX. I am simply going to use the throttle cable assembly I got off of the SX and weld the tip of the SX pedal arm onto the end of the Z car pedal arm. The cable is just about the perfect length for the Z. My motivation for this is that I am planning on using a shaved, smoothed and coated 1976 FI intake (without EGR). The switch to a cable linkage will allow me to go one step further and remove the shaft linkage "towers" from the intake. Talk about clean! Then my polished stainless fuel rail will really shine!!!!